Traffic signal with electric control



March 11, 1941. TQNE 2,234,610

TRAFFIC SIGNAL WITH ELECTRIC CONTROL Original Filed July 20, 1927 5Sheeis-Sheet 1 E-W 5mm CAR March 11, 1941. T. TONE TRAFFIC SIGNAL WITHELECTRIC CONTROL 5 Sheets-Sheet 2 March 11, 1941. 'r. TONE TRAFFICSIGNAL WITH ELECTRIC CONTROL Original Filed July 20, 1927 5 Sheets-Sheet3 a 2 z 5 Z March 11, 1941. "r. TONE TRAFFIC SIGNAL WITH ELECTRICCONTROL 5 Sheets-Sheet 4 Original Filed July 20, 1927 Thmnaa BTWInventor Attorney 19:26 Swarm 23w m March 11, 1941. T. TONE 2,234,610

TRAFFIC SIGNAL WITH ELECTRIC CONTROL Original Filed July 20, 1927 5Sheefis-Sheet 5 d Mei i207 Mil 4&5 n40 Patented Mar. 11, 1941 UNITEDSTATES TRAFFIC SIGNAL WITH ELECTRIC CONTROL Thomas Tone, Gilman,

Iowa, assignor to Nachod & United StatesSignal 00., Incorporated,Louisville, Ky., a corporation of Kentucky Continuation of applicationSerial No. 207,172,

July 20, 19

27. This application January 7,

1937, Serial No. 119,536

, '17 Claims.

The present application is a continuation of application Serial Number207,172 filed by Thomas Tone on July 20, 1927 and entitled Trafficsignal controlled by vehicles." For any proceedings relating to thiscontinuation application reference may be made to the file of theoriginal application above identified, which is being abandoned in favorof this continuation application.

The invention relates to automatic self-regulating trafilc signals, andthe means for operating same.

As is well known, the regulation of traflic at intersections where thereis a large amount of trafllc is now quite a serious problem. Thus it isthe principal object of this invention to provide means whereby theregulation of such traific will be greatly improved by subjecting thesignal to control by vehicles using the intersection.

It is a further object of this invention to provide a trafiic signal forinterfering tramc lanes adapted to be controlled either manually,automatically orby vehicles, so that there will be a minimum amount ofdelay to tramc, in such a way:

1. That the right-of-way will always be on one or the other of saidtraflic lanes,

2. That the right-of-way will never be on interfering lanes at the sametime,

3. That the right-of-way will be immediately transferred to a vehicleapproaching on a lane not receiving the right-of-way, if there are novehicles operating the signal on the lane then receiving same,

4. That the right-of-way will not be immediately transferred to avehicle approaching on a lane not receiving the right-of-way, if thereare vehicles operating the signal on the lane then receiving same,

5. That the right-of-way, under Condition 4, will be transferred to thewaiting vehicle a predetermined time after the last operation of thesignal by vehicles moving on the lane then receiving same,

6. That the right-of-way, when operated in response to an approachingvehicle, will be established for a predetermined time sufficient topermit a vehicle, traveling at the usual rate of speed, to pass theintersection,

7. That the right-of-way will be retained by successive vehicles movingon a lane receiving the right-of-way, provided that each successivevehicle operates the signal within a predetermined time after eachpreceding operation thereof,

8. That the right-of-way for each succeeding vehicle, in Condition 7,will be re-established for a predetermined time after each operation ofthe signal,

9. That the right-of-way will be retained'on the lane then receiving theright-ofway, if two vehicles on interfering lanes simultaneously callfor an operation of the signal,

10. That the right-of-way, in Condition 9, will be transferred to thewaiting vehicle a predetermined time afterv the last operation of thesignal by vehicles moving on the lane then receiving same,

11L That the right-of-way, when retained to permit a continuous streamof traffic topass on onelane, may be arranged to be automaticallyinterrupted at predetermined times,

12. That the right-oi-way, when retained to permit a. continuous streamof trafllc to pass on one lane, may be arranged to be interrupted atpredetermined times only when vehicles approach on an interfering lane,

13. That the right-of-way will be automatically alternately andrepeatedly established at predetermined times, first to one lane, thento the other, and so on cyclically, when a continuous stream of trafficoperates the signal on each lane,

14. That the cyclical establishment of' the rightmf-way will be governedby a constantly operating timing switch, whose operation and timingcontinues at all times regardless of trafiic conditions, V r

15. That when the right-of-way is transferred in response to a vehiclecalling for same within a predetermined time after operation by avehicle on a lane previously receiving same, it will be automaticallyreturned to said lane when vehicles cease to operate on the lane towhich it was transferred,

16. That the right-of-way, after being established on other lanes, willalways automatically return to one certain lane,

17. That the right-of-way may be selectively established on either laneby an approaching street car, but when the car occupies its usualstopping point, the signal may be selectively established only to thelane in which the said car is operating,

18. That a warning signal will be displayed for a predetermined timewhen the right-of-way is automatically interrupted within apredetermined time after the signal was operatedby a vehicle on the lanereceiving same, g

19. That the warning signal will not be displayed when the right-of-wayis interrupted after vehicles cease to operate on the lane previouslyreceiving same,

20. That the display of the warning signal will be progressivelyshortened when the right-of-way is automatically interrupted between thetimes provided in Conditions 17 and 18,

21. That, during the absence of vehicular traific on either lane, theright-of-way will be alternately and repeatedly transferred atpredetermined times in such a way that the right-of-way will display fora predetermined time, first on one lane and then on the other and so ,oncyclically, all of the various conditions previously set forth beingarranged to accompany the operation of the signal under vehicleoperation,

22. That, during the absence of vehicular traf- 110, the right-of-waywill be normally alternately and repeatedly presented for predeterminedtimes to the several streets, which will automatically revert toright-of-way presentations of shorter duration when light traflicoperates on each street, and which will automatically re-establish thenormal presentations of the right-of way when a continuous stream oftrafllc operates the signal on each street,

23. That the right-of-way may, under certain conditions, be arranged toremain always on the lane to which it was last actuated,

24. That one or more of the previous conditions may be omitted or usedin various combinations according to the particular requirements of theintersection,

25. That by simple alterations, ali time intervals and responses totraffic in the various lanes may be adjusted to meet variousdistributions and densities of trafllc.

These and other objects and advantages of my invention, not specificallyenumerated above, are

' more fully set forth in the following description made in connectionwith the accompanying draw- !ngs, in which like reference charactersrefer to similar parts throughout the several views, and in which:

Figure 1 is an elevational view of the timing mechanism for my signal,the enclosing casing being shown in vertical section;

Fig. 2 is an enlarged vertical section of a portion of the mechanismshown in Fig. 1 taken along operating shaft 34;

Fig. 3 is a vertical section taken along line 3-3 of Fig, 2 showing theend of drum 31;

Fig. 4 is a vertical section taken along line 5-4 of Fig. 2 showingspiral spring 52 and commutator 53;

Fig. 5 is a vertical section taken along line 5-5 of Fig. 2 showing theelectrical connections of commutator 53;

Fig. 6 is a vertical section taken along line 55 of Fig. 2 showing stoplugs 53g on disk 53!;

Fig. 'I is a vertical section taken along line l-I of Fig. 2 showing therelation of keys II and cam shell 42;

Fig. 8 is a vertical section taken along line 3-8 of Fig. 2 showing anend view of timing member 33;

Fig, 9 is a. vertical section taken along line 33 of Fig. 2 showing anend view of timing disk I001);

Fig. 10 is a vertical section of the'street switch taken along line i0l0of Fig. 12, showing the arrangement of spring members 23 and supportplates 33;

Fig. 11- is an enlarged vertical section taken along line ll-Il of Fig.12, showing the electrical contacts 25-26 and pivot studs 3|;

Fig. 12 is a partial plan view of the street switch sectionally showninFigs. 10 and 11;

Fig. 13 is a diagrammatic representation of the apparatus employed tocontrol the signal by a motorman on a street car;

Fig. 14 is a wiring diagram for the device;

Fig. 15 is an isometric view showing a street intersection with cartracks thereon and the signal at the center of the intersection; and

Fig 16 is a vertical section taken along line l6--l5 of Fig. 2 showingthe relation of contacts MT and cam 940, which cam resets triggers 94k.

GENERAL Referring now to Fig. 15 of the drawings, it will be observedthat the invention utilizes a signal device, and, while this device maybe made in various forms, in the embodiment of the invention it isillustrated as a post 20 having means thereon for alternately permittingtraffic to proceed on one street while restraining traffic on the other.Such means is indicated by the words "stop" and "go shown on post 20. InFig. 14 the lamps for-"illuminating the words stop and go" are indicatedby characters R and G respectively. A warning signal 2| visible to bothstreets is also shown at the top of post 20, which warning light isfurther indicated in-Fig. 14 by the character A.

The signal device is adapted to be controlled by street switches 22 and22A placed a suitable distance from the intersection, and, while thisdistancevmay be varied for different occasions, it is intended that thedistance will be such that a vehicle, traveling at the usual speed forvehicles at intersections, will have timeto stop before reaching theintersection, if the signal device is prevented from changingimmediately as a result of tramc moving on an intersecting thoroughfare.

It is also intended to have the signal device controlled by a motormanon a street car, and for the details of the apparatus provided for thispurpose reference may be made to Fig. 13.

In Fig. 13 the trolley wire on the E-W street is indicated by B2 whileB3, BI 'and B5 represent contact segments. BI represents the trolleypole of an E-W street car, while B5 represents a contact member forengaging segments'B3, B4 and B5 on the E-W street. The contact member B6is connected by a suitable conductor "to a switch I12 locatedin the cabof -th'e .;E--W'-street car B.

In Fig. 15 the streets are designated by N, S, E and W, and car tracksare indicated by 116- and H1. While not shown in Fig. 15, it is intendedthat the street cars for each street be equipped as illustrated in Fig.13.

Therefore, it is to be understood that each N-S street car is providedwith a similar contact member B6, and a switch I13 corresponding withswitch I12 of the E-W street car. Likewise, the trolley wire on the NSstreet is provided with contact segments B3, B4 and B5 arrangedsimilarly to that illustrated in Figure 13. However, contact segments B3and B5 on the EW'street are electrically connected and connected toconductor 256 for energizing relay coil I56, while the similar contactsegments B3 and B5 on the N-S street are electrically connected, andconnected to conductor 253 for energizing relay coil l56a. Likewise, theconnections for the contact segmentsBl on the E'W and N-S streets aretransposed. Thus, as illustrated in Figure 13,.the contact segment B4 onthe E-W street is connected to conductor 253 for energizing relay coil156a, while the corresponding contact segment B4 on the NS street isconnected to conductor 256 for energizing relay coil I66. The aforesaidelectrical connections are diagrammatically illustrated in Figure 14, inwhich figure the contact segments B3 are not indicated inasmuch as eachis electrically connected to its corresponding contact segment B5.

Contact segment B3, for each track, is preferably placed approximatelyat the location of its corresponding street switch 22 or 22A. Contactsegment B4, for each track, is placed between its associate contactsegment B3 and the usual stopping point for the street car, whilecontact segment B5, for each track, is placed so that the contact memberB6 will be in engagement therewith while a car is stopped at theintersection.

S'rnrzar SWITCHES While the street switches 22 and 22A may be variouslyconstructed, in the embodiment of my invention they are shown in Fig. 10as comprising a. casing 22a having a longitudinal conduit 22b throughwhich extend conductors 23. The casing 22a has a series of pairs ofupstanding partitions 22c forming narrow channels in which are disposedvertically movable blocks 24. As illustrated in Fig. 11, each block 24has a centrally located recess, within which is disposed a movablecontact member 25 and stationary contacts 26. The stationary contacts 26are supported by and extend through a small casing 21 communicating withconduit 22b, and having conductors 23 connected thereto. The recess ineach block 24 is closed at its bottom by a plate 28 that embraces casing21. As shown in Fig. 10, casing 22a also has wide vertically extendingchannels between the pairs of partitions 220 for receivingsemi-elliptical springs 28 that support plates 38. As furtherillustrated in Fig. 11, plates 30 have side portions fitted within sideflanges of easing 22a. Plates 38 also have downwardly extending lugs 38apivoted on studs 3| threaded into the sides of block 24. It will beunderstood that the number of plates 36 and blocks 24 will vary with thelength of the switch casing 22a, there being two of the plates 30 shownin the vertical section Fig. 10. End plates 301) are secured to casing22a, and plates 30 and 30b are covered by a sheet of flexible material380 secured by an overlying strip 30d fastened by suitable screws 30e.The blocks 24 are limited in their upward movement by headed screws 24athat have their heads movable in recesses 22d fashioned in casing 22a.

TIMTNG MECHANISM The timing mechanism for the signal device ispreferably held in a casing 32, and, while this casing may be located atany convenient place. in Fig. 15 it is shown disposed in the sidewalk.The mechanism within the casing is partly shown in Fig. 1, and comprisesa motor 33. A shaft 34 is driven by the motor 33 through reducing gears35 and 36. The shaft 34 is journaled in a plurality of partitions 32athat extend vertically in casing 32, and said shaft at its end oppositemotor 33 extends into a drum 31.

As shown in Fig. 2, the drum 31 is disposed between two adjacentpartitions 32a, and has a compression spring 38 that engages one innerendthereof. The other end of spring 38 engages a friction clutch cone39splined on shaft 34. The cone 39 is adapted to move into and out ofengagement with an inner conical surface of a cooperating clutch member40 secured to drum 31.

The drum 31 also has guide keys 4| secured to opposite sides of itsinner wall by countersunk screws. A shell 42, longitudinally movable onshaft 34, is disposed within the drum 31, and has slots42a in oppositesides thereof embracing keys 4|. The shell 42 is also formed at one endwith a plurality of cam ratchet teeth 42b. The teeth 42b co-operate withsimilarly formed teeth 4311. on another short shell 43. Shell 43 is alsoprovided with a hub, keyed to a shaft 34a and journaled on the end ofshaft 34. In Fig. 1, shaft 34a is shown journaled in the end pair ofpartitions 32a. Shell 43 also has a pair of oppositely disposedangularly movable dogs 44 projecting from its end face through arcuateslots 45a formed in an end disk or closing member 45 of drum 31. 'As

shown in Fig. 3, member 45 is secured to the end of drum 31 bycountersunk screws.

The member 45 carries on its outer face oppositely disposed pairs ofradially movable dogs 46 that have pointed notches in their outer endsadapted to engage pointed or beveled sides of dogs. The dogs 46 alsohave slots therein,- through which extend pins 41 projecting outwardlyfrom member 45, forming guide means for the radially movable dogs 46.Dogs 46 are urged outwardly radially by compression springs 48 thatreact against lugs-45b. Each dog-44 is attached to a tension spring 49.The other end of each spring 49 is connected to 3. lug 45c projectingfrom member 45.

The periphery of drum 31 is provided with ratchet teeth 31a adjacentmember 45. A-pawl 50 co-operates with ratchet teeth 31a, and is pivotedon a rod 5| projecting from one of the partitions 32a.

The shaft 34a, as shown in Fig. 4, is connected to one end of a spiralspring 52. The other end of spring 52 is connected to a drum portion 53aof a commutator 53 journaled on shaft 34a.

The commutator 53 is of insulating material, and has at its peripherycontact'segments 53b of metal, separated by insulating portions 530. Asshown in Fig. 5, conductors 54 connect alternate segments 53b, which, asshown in Fig. 2, are connected by conductors 54a to collector rings 55and 56 that surround disk portions 53d.and

53c of commutator 53. A brush 53h engages the segments 53b, whilebrushes 55a and 56a engage collector rings 55 and 56. As shown in Fig.6, commutator 53 also has a disk portion 531 that has alternatelyarranged stop lugs 53g disposed adjacent its edge and at opposite sidesthereof.

As shown in Fig. 2, a. rectangular bar,51 extends through apertures inthe end pair of partitions 32a, and is arranged to slide and not rotatetherein. The bar 51 has a pair of projecting arms 51a and 51b thatembrace opposite faces of disk 53;, and an arm 51c that is employed inmoving the bar 51. Bar 51 also carries a pair of contact members 51d and51e that are connected to conductors 230 and 23l. The contacts 1, 51dand 51e are, in the movement of member 51,

adapted to be connected to contact members 60 and 66a, respectively,which are connected to conductors 229 and 233.

As shown in Fig. 1, a slidable bar 63 is provided with a hooked endadapted to engage arm 510 for moving bar 51 to the left. Bar 63 isnormally biased to the right by a compression spring 64 that reactsbetween a partition 32a and a collar 65 fixed to bar 63. A stop collar66, secured to bar 63, serves to limit the movement of the bar to theright. At its other end, bar 63 has an upstanding arm 63a carrying anarmature gage a'iiepending end of an arm 83c to discon- -connectcontacts II and l2.

nect a pair of contacts II and 12 when the bar 63 is moved to the left.A tension spring 9311 is attached to one end of arm 63c and to astationary support 63c projecting from a partition 32a, for holding arm63c normally in position to Bar 63 also has, pivotally connectedthereto, the vertical ends of a pair of bell-crank levers 13 that arepivoted at their corners to upstanding arms 14a carried by a horizontalbracket 14 that extends between several of the partitions 32a. Thehorizontal ends of said bell crank levers are slotted, andreceive pinsI5 carried by vertically movable arms 19 that are slidable in bracketI4.

Another slidable bar 11 is provided, being disposed below and at oneside of the bar 63, and is adapted to have one end thereof engage arm51c for moving bar 51 to the right. Bar I1 is normally biased to theleft by a compression spring He that reacts between a partition 32a. anda collar 'IIc fixed to bar 11. A stop collar 'IId secured to bar TIserves to limit the movement of the bar to the left. At its other end,bar 'II has an upstanding crm IIa carrying an armature I9 of anelectromagnet I9. Arm Ila also carries a rightangled extension 111)adapted to engage a depending end of an arm 92 to disconnect a pair ofcontacts 93 and 84 when the bar TI is moved to the right. A tensionspring 95 is attached to one end of arm 82 and to a stationary support99 projecting from a partition 32a, for holding arm 92 normally inposition to connect contacts 93 and 94. Bar 11 also has, pivotallyconnected thereto, the vertical ends of a pair of bell crank levers 81that are pivotally connected at their corners to a pair of arms 14a. Thehorizontal ends of said bell crank levers are slotted, and receive pins88 secured to vertically movable arms 99 that are slidable in bracket14. I

Shaft 34 has secured thereto four timing members 99, 9|, 92 and 93,constructed of insulating material. These members are similar, thereforethe description of one will suiiice for all of them. For this purposemember 93 has been selected, and reference may be made to Figs. 2 and 8.

Member 93 comprises a disk portion 93a having a series ofcircumferentially spaced open slots 93b at its periphery. The diskportion 93a also carries a pair of concentric contact rings 93c and 93dthat are connected by conductors 93a to collector rings 93 and 939,which rings surround the peripheries of disk portions 93):. and 93i,respectively, of member 93. Rings 93):. and 93i are engaged by brushes93:1 and 931' that extend from one wall of casing 32. Member 93 alsohas, secured to one end of its central hub, a plurality of radiallyextending arms 93; made of resilient material, each of which has aprojecting lug to which is ivoted a trigger 93k biased inwardly by aspring 93m secured to the outer end of arm 937'.

Triggers 93k have shoulders adjacent their outer ends arranged to engagethe edge of disk 93a. to hold arms 937' in an outward position, as shownat the bottom of disk 93a in Fig. 2, thereby holding contact members 93nout of engagement with rings 93c and 93d. The free end of each triggermember 9310 is arranged to be engaged by a horizontal extension 990. ofarm 99 already referred to. The arms 937' are arranged to be engaged andrestored to normal by a circumferentially adjustable hook cam 93ocarried by an upstanding bracket 93p. In Fig. 8 only four of these arms931 are illustrated, but it is to be understood that there will be onefor each hole indicated in the hub of member 93.

To assist in the understanding of the construction of members 99, 9I and92, corresponding parts have been designated by similar characters.

Shaft 34 also has secured thereto timing members 94E and 96N that aresimilar in construction to members 99 and 93. The parts of members 94Eand MN that correspond to similar parts of member 93 have beendesignated by similar characters. It is to be observed, however, thateach trigger 94k of member 94E is provided with an insulated contactmember 94s that is adapted to engage stationary c'ontact members 94t-94Tcarried by an insulating-bracket 94u. Each trigger 9610 of member 96Nhas a similar insulated contact member 968 that is adapted to engagecontact members 98t-96T carried by insulating bracket 9614.

Electro-magnets 95 and 96 are provided, and have armatures 95A and 96A,respectively, to which are secured downwardly extending arms 95b-and96b. These arms have angled levers 91 and 99 pivotally attached to theirlower ends. Levers 91 and 99 have horizontally projecting arms 91a. and98a at their lower ends that are adapted, at certain times, to extendunder and lift triggers 94k and 96k respectively. The upper ends of saidlevers have horizontal extensions 91b and 99b that operate betweenhorizontal projections carried by downwardly extending brackets 99.

As shown in Fig. 2, shaft 34 also has journaled thereon, adjacent motor33, a timing member I99 that is held in place by a pair of collars I93.Member I99 has at one end a gear I99a meshing with a gear I9Ia carriedon a member I9 I. Member I9I also hasanother gear I9Ib thereon, meshingwith a pinion I92 secured to shaft 34.

Member I99 also comprises a disk I99b that has secured to opposite sidesthereof pairs of cams I94 and I95, respectively, that arecircumferentially adjustable in slots I99c shown in Fig. 9.

Cams I94 are located to the right of disk I99!) and are adapted tooperate a contact closing member I96. The member I96 has an elongatedslot that receives screws I 91 secured in a stationary bracket I98 forfrictionally securing member I96 in its operative positions. The memberI96 also carries contacts I99 and I99b. Normally, contact I99b engages astationary contact I99a. but, when the member I96 is operated by camsI94, the latter contacts are disengaged and contact I99 engages astationary contact I I9.

Cams I95 are located to the left of disk I99b and are adapted to operatea contact closing member III. The member III has an elongated slot thatreceives screws II2 secured in the stationary bracket I99 forfrictionally securing member III in its operative positions. The memberI also carries contacts I99b and H3. Normally, contact I99b engages astationary contact I99a, but, when the member I96 is operated by camsI95, the latter contacts are disengaged and contact II3 engages astationary contact II4.

As shown in Fig. 9, disk I99b also has on its periphery a. camprojection I99d. This projection is adapted, in the revolution of saiddisk, to operate a downwardly-movable contact-closing member I I5 thatcarries at its lower end a contact I I6. When the member I I5 is thusoperated, contact II6 engages a stationary contact III carried by thelower wall of casing 32. The member II5 also has an elongated slot thatfreely receives screws II8 secured in a stationary bracket II9 carriedby a partition of casing 32. A tension spring I24 is provided for memberII5 that serves to maintain contacts H6 and I I1 disengaged nor? 1mally. The projection MM is also adapted, in the revolution of diskI001), to operate an upwardly- SUMMARY or MECHANICAL OPERATION Theoperation of the mechanical parts so far described may be summarized asfollows: When a vehicle operates one of the street switches 22 or 22A,the plates 30 are depressed against the pressure of springs 29.Depending upon the position of the vehicle, these plates swing about oneor all of the pairs of pivots 3|, and one or more of the blocks 24 aredepressed, thus bringing a contact member 25 into engagement with a pairof stationary contacts 26 and closing a circuit through said contacts.

Motor 33 continuously rotates and, through gears 35 and 36, rotatesshaft 34. Compression spring 38 normally holds clutch cone 39 inengagement with clutch member 40, causing drum 31 to rotate, which inturn imparts rotary movement to shell 42 through keys 4i. Plate 45 issecured to drum 31 and accordingly rotates therewith. The rotation ofplate 45, through tension springs 49 and associate dogs 44 and 46,rotates shell 43. Shell 43 is secured to shaft 34a, and, when rotated,winds spiral spring 52, thereby placing shaft 34a under tension torotate.

Referring to Figs, 2 and 3, it will be observed that the tension ofspiral spring 52 acts against the pressure of compression spring 38,tension springs 49 and the latching action of dogs 44 and 46. Thus, whenthe tension of spiral spring 52 is suflicient to overcome this pressure,dogs 44 will rapidly disengage the dogs 46 with which they are shownengaged in Fig. 3, and move to the opposite ends of arcuate slots 45aand engage the other dogs 46. This action will cause shell 43 to rotaterelative to shell 42 and, by reason of cam teeth 43a and 43b, also causeshell 42 to movelongitudinally to the left and thereby disengage clutchcone 39 from clutch member 40 carried by drum 31. When the tension ofspiral spring 52 decreases sufiiciently, the tension springs 49 willreturn dogs 44 back into engagement with the dogs 46 as shown in Fig. 3.Spiral spring 52 is thus maintained under definite tension, which tendsto rotate shaft section 34a. It is pointed out that the purpose of dogs46 is to prevent unnecessary movement of dogs 44 in arcuate slots 45a,and to withhold any such movement until there is considerable diiferencein pressure between spiral spring 52 and compression spring 38, ortension springs 49.

Rotation of shaft 34a is normally prevented by one of the arms 51a or51b of bar 51 engaging a stop lug 53g on member 53f. Bars 63 and 11 areadapted to engage an arm 510 of bar 51, to shift bar 51 to the left orright, and accordingly cause the arms 51a and 51b to engage alternatelystop lugs 539. When bar 51 is thus shifted, spiral spring 52 causes thecommutator 53 to rotate partially as determined by the spacing of stoplugs The members to 93, 94E and 96N, are continuously rotated with shaft34, and the trigger members 90k, 9Ik, 92k, 93k, 94k and 96k, arenormally in the position shown for triggers 93k and 94k at the bottom ofthe disks 93a and 94a in Fig. 2. As themembers 90 to 93, 94E and "Nrotate, the spring arms carrying the triggers are engaged by theirrespective hook cams 90o, 9Io, 920, 930, 940 and 960, and are swungoutwardly. When so swung, the shoulder on each trigger engages the edgeof its respective disk 90a, 93a, 94a, 96aand is held in that positioEach trigger remains in that position until it is lifted by itsrespective arm 89, 16, or lever 91, 98. When, for example, the trigger9310 is lifted, it will remain in that position and hold rings 93c and93d connected by contact member 9311. until the cam 930 is reached atthe bottom, when it will be swung outwardly and cause rings 93c and 93dto be disconnected.

When, for example, the trigger 94k is lifted, so that rings 94c'and 94dare connected, an in'sulated contact 948 carried by trigger 9410 willengage contacts 94T and Mt a few seconds before its cam 94o is reachedand before its corresponding member 93 operates to change the signal.

The disk I00b is constantly rotated at reduced speed by motor 33 throughgears I00a, IOIa, IOIb and I02. As disk I04, namely, the one in advancein the direction of rotation, will engage under a projecting lip ofcontact closing member I06, thereby raising said member so that contactsI09 and H0 will be connected and contacts M911 and I09b disconnected.The member I06 will remain in this raised position until the other camI04 engages the upper portion of said projecting lip and lowers memberI06. As previously mentioned, the member I 06 is frictionally held ineither its raised or lowered position.

The cams will likewise operate to raise and lower member III, so thatcontacts H3 and H4 will be connected and contacts I08a and I08bdisconnected, until a second cam thereby disconnecting contactsreconnecting contacts I08a and I091),

As disk I 00b rotates, its cam projectionv I00d alternately andrepeatedly actuates members H5 and I20 to close temporarily pairs ofcontacts I22-I23 and II6-II1 respectively. These actuations occur atpredetermined times with respect to the operation of contacts by pairsof cams I04 and I05. For example, cams I04, on the right side of diskI001), are preferably positioned with reference to cam I00d so that theforward cam I04 will raise member I06 to connect contacts I09 I l0 anddisconnect contacts I09a-I09b before cam I00d operates member I20 toclose contacts I22- I23, while the trailing cam I04 is set to restorethe normal connections of member I06 after cam I00d permits member I20through action of spring I25 to disconnect contacts I22-I 23. A similarrelation likewise prevails between the operation of members III and H5by cams I05 and I00d. It is to be understood, however, that cams I04 andI05 may also be adjusted to operate the r respective contacts eitherbefore or after the cam I00d operates. Particular attention is directedto the relatively wide range of adjustment for camsI04 and I05 asindicated in' Fig. 9.

H3 and H4 and I05 at the left side ofthe disk I00b I002) revolves, oneof the cams I05 engages member III,

RELATIVE Sarrixos or TIMING LIECHANISM Timing members 90, 9|, 94E andcam operated contacts I08a-I08b, II3II4, and IIB-III are utilized in thecontrol of the go signal for the EW street, while timing members 92, 93,95N and cam operated contacts IBM-109b, I09I I and I22-I23 are utilizedin the control of the go" signal for the NS street. The timing membersfunction only when a vehicle operates its corresponding street switch,but the cam operated contacts are alternately and repeatedly operatedfor short intervals regardless of traffic conditions. Therefore, it willbe obvious that vehicle actuation of the street switches is entirelyhaphazard relative to the predetermined time of operation of the camoperated contacts I08a II'IBb, II3-I I4 and II5I I! for the EW street,and cam operated contacts I99a-l09b, I09-I I0 and I22I 23 for the NSstreet.

Disk IIIIIb rotates slower than shaft 34 and for the purpose ofillustration may be said to make one revolution every two minutes.Accordingly 'cam- IIlDd on the periphery of disk IIIIIb, alternately andrepeatedly causes pairs of contacts Il6--I I1 and I22I23 to closemomentarily, first one pair, followed one minute later by the otherpair, and so on cyclically.

Cams I05 are adjusted to close pairs of contacts II3I I4 and open pairsof contacts I081;- IIIBb for a definite interval, during which time thecontacts II5I I1 arepreferably operated.

Similarly, cams I04 are adjusted to close pairs of contacts IDS-I I0 andopen pairs of contacts I09a.l99b for a definite interval, during whichtime the contacts I22-I23 are preferably operated.

Thus the contacts operated by cams I94 and I05 are alternately andrepeatedly operated for definite intervals, first those operated by camsI04 and one minute later those operated by cams I95, and so oncyclically.

Timing members 90 and -9I are simultaneously placed into operation by avehicle actuating a street switch on the EW street. Member 9| isadjusted so that its contacts 9lc-9Id will remain closed for 10 secondsafter operation, while member 90 is adjusted so that its contacts 900--99d will remain closed for seconds after operation, or 5 seconds longerthan member 9I.

Timing members 92 and 93 are similarly adjusted and operated for the NSstreet. Member 93 being set for 10 seconds and member 92 being set for15 seconds.

Timing member 94E is adjusted to open its contacts 94c94d after member93 opens its contacts 930-9311. This is to assure that timing member 94Ewill not restore before member 93 when they are placed into operationsimultaneously.

Contacts 94t-94T of timing mechanism 94E are employed to control awarning signal, and are adjusted .to close for a deflnte time during theoperation of member 94E. The adjustment of contacts 94t-94T is madeaccording to the setting of contacts 93c93d of member 93,such that thecontacts 94t-94T will close and cause the warning signal .to display fora definite time before member 93 disconnects contacts 93c-93d to yieldthe control of the go signal to EW street when the members 94E and 93are placed into operation simultaneously. Under light traflic, themember 93 may be placed into operation' before member 94E, then thedisplay of the warning signal will be shortened by the amount of timeelapsing between the operation of members 93 and 94E.

Obviously, if the amount of time elapsing between theoperatlon ofmembers '93 and 94E is equal to .the normal time of display of thewarning signal, then no warning signal is necessary, since .the vehicleoperating member 93 had sufficient time to clear the intersection, andtherefore the immediate transfer of the "go signal without a warningsignal as provided for in my invention is desirable.

Under continuously moving traffic, on the NS street, member 93 will berepeatedly operated, and accordingly the final timing of member 93 willbegin substantially with the operation of member 94E. It is seen,therefore, that the warning signal is displayed for its full time onlywhen waiting trailic on one street causes continuously moving trafllc onthe other street to be abruptly stopped or when vehicles on each streetplace members 94E and 93 into operation simultaneously.

Timing mechanism 95N is similar to member 94E and is similarly adjustedand set according .to timingmember 9| for displaying the warning signalfor traffic moving on the EW street.

Y Relay system To accomplish the objects of my invention, various relayshaving magnet coils and armatures controlling electrical circuits, areused in addition .to the timing mechanism in casing 32, and these areshown in my wiring diagram Fig. 14.

The arrangement of the circuits and relays is generally in duplicate,one set being provided for one street and a duplicate set for the other.

The relay, having coils I49, I49 and I50,.is provided with armatures I5Iand I5Ib, and is employed to register operations for the EW street.Normally these coils are tie-energized and armature I5Ib engages backcontact I55, but when either of the coils is energized the lattercontact is disengaged and armature I5I engages front contacts I52, I53and I54. The relay having coils Ba, 9:; and IBM is the equivalent forthe N S street.

The relay having coils I33 and I34 15 provided with armatures I35, I35e,and I35b, and is employed to transmit selectively an operationregistered by the relay having coils I49, I49 and I59 to the timingmechanisms in casing 32. Normally these coils are de-energized andarmature I35e engages back contact I35, but when either of the coils isenergized the latter contact is disengaged and armatures I35 and I35bengage front contacts I38 and I31 respectively. The relay having coilsI33a and I34a is the equivalent for the NS street.

The relay having coils I43 and I44 is provided with armatures I45 andH55, and is employed to cause the go signal to return to the EW streetunder various conditions of operations. Normally the coils arede-energized and neither of the armatures I45 or 5!: engage contacts.When either of the coils is energized, the armatures are raised andarmature I45 enga es a front contact I45. The armature I45b isconstructed so that it will not engage contact I41 while it is beingraised or remains in its raised position. When the coils arede-energized, armature I45 will disengage contact I46 and armature l45bwill momentarily engage contact I41 in its movement to its normalretracted position.

alent for the N-S street. The relay having coil I39a is provided witharmatures Ba and I400, and is employed to operate selectively the relayhaving coils I43 and I44 when a vehicle on the N-S street calls for the"go signal within a-predetermined time after the last vehicle registerson the E-W street to hold the go signal. Normally the coil I39a isde-energizedand neither. of the armaturesl40a or I400 engage contacts.When the coil is energized the armatures are raised and engage frontcontacts I4Ia and 2:: respectively. The relay having coil I39 is theequivalent for the N-S street.

The relay having pairs of coils I21-I23 and I2'Ia-I28a is athree-position relay, and is employed to transmit selectively operationsregistered by relays having coils I48-I49-I50 and I48a-I49a-I 50a, inthe event such registrations are received substantially at the sametime, and it is further arranged to give preference to the street forwhich the go" signal was already set. Normally the coils arede-energized and the plunger type armature I29 is biased to a centralposition, and pairs of contacts I3l-3ll9, I30- 3), I30a-3II and I3Ia-3I2are engaged. When the plunger is moved to the left by either of thecoils I21-I28 in response to an E-W street operation, pairs of contactsl3l-309 and I30 3H] maintain their engagement while pairs of contactsI3Ua-3II and I3Ia-3I2 are disengaged. It is important to note that whenthe plunger is moved to the left, a contact I32 is then connected tocontact I3I. When the plunger is moved to right by either of the coilsI2'Ia-I28a in response to an N-S operation, the reverse operation of thecontacts is effected and a contact I32a is connected to contact I3Ia.The four coils are substantially equal in power, and are arranged sothat both coils I2I-I28 will be energized in response to an E-Woperation if the go signal is already displaying to that street, whileonly one coil I28a will be energized if an N-S operation is registeredat that time. Thus the plunger will shift to the left by reason of thegreater power provided by the pair of coils l2I-I28. The reverseoperation will occur if the go signal is displaying to the N-S street,since the. pair of coils I2'la-I28a will provide greater power thanthesingle coil I28.

Another'three-position relay having coils I56 and I56a is provided, andis employed to control selectively the go signal in response tooperations by a motorman on a street car. Normally the coils arede-energized and the plunger type armature I5! is biased to a centralposition, and pairs of contacts 3II-325, 3I8-326, BIS-321, 320-328,32I-329, 322-330, 323-33I and 324- 332 are engaged. When the plunger ismoved to the left by coil I56, all of the pairs of contacts engaged inthe central position are opened and contacts 3II-3I8 and 3I9-'320 areconnected. When the plunger is moved to the right by coil I56a, all ofthe pairs of contacts engaged in the central position are opened andcontacts 323- 324 and 32I-322 are connected.

The relay having coil I64 is provided with an armature I65 and isemployed to control the circuit of a warning signal 2| for both streets.Normally coil I64 is de-energized and no contact is engaged, but whenthe coil I64 is energized its armature I65 engages a front contact I66.

Ormnon The operation of my invention may be conveniently divided intofive distinct parts, as follows:

l. The simple or usual method of operating the go signal, which isordinarily brought about by the operation of a street switch bringinginto action a timing unit to prevent a further change in the go" signalfor 10 seconds.

2. The positive transfer of the "go signal, which is effected byelectro-magnets 36 and 96, whereby one street takes the go signal from astream of traflic on another street for at least v 10 seconds.

This positive operation of the go" signal may be sub-divided into twodistinct operations as follows:

A. The automatic positive transfer of the go" signal", which is effectedjointly by the operation of a street switch on the street not receivingthe "go signal, and the closing of a pair of cyclically operatedcontacts II3-I I4 or I03-I I0, whereby the traffic on the said streettakes the go signal from a stream of trafllc on another street.

B. The manual positive transfer of the go signal, which is efiected bythe operation-of a manual switch located in the cab of a street car,whereby thejgo" signal is immediately taken from a continuous stream oftraffic on one street and given to another. I

3. The automatic cyclic transfer of the go" signal, which is broughtabout at certain definite times regardless of trafiic on either street,by the alternate and repeated closing of sets of contacts IIB-III andI22-I23.

4. The automatic return of the go signal, which is the automatic returnof the go signal to one street when traillc ceames to use the go signalon another. There are also two methods of automatic return:

A. The vehicle operated. automatic return of the go signal, which is theautomatic return of the go signal to the street from which it was taken,by the operation of a street switch on the street to which it wastransferred.

B. The arterial automatic return of the go signal, which always returnsthe go signal to a given street when traiiic ceases to use it on otherstreets. 4

5. The automatic display of a warning light, which is provided only whentrafilc on either street interrupts a continuous stream of traific onthe other, by a positive transfer of the go" signal.

Under various conditions of trafiic, different combinations of the aboveoperations are utilized to provide a minimum amount of delay to thetrafilc. However, before giving specific illustrations as to theoperation of my invention under various conditions of trafilc, I willfirst describe each operation enumerated above by itself. It beingunderstood that, where the operation is applied to a' specific street,the same operation for the other street will occur if the trafiicconditions are reversed, in which case corresponding apparatus providedfor the other street will be utilized in the operation.

PART 1 The simple method of operating the go signal This method ofoperating the go signal is employed either to transfer or retain the "gosignal, as the case may be, when there is insuf- 'ficient traflic oneither street to cause an operation of the signal by the positivetransfer method.

The relay having magnet' coils I43-I43I56 is employed to register signaloperations for the E-W street, and may be energized by: an operation ofthe street switch 22A; a movement of plunger I51 to the left by magnetcoil I56; the closing of cyclically operated contacts II6II1, or; anoperation of the relay having magnet coils I43I44'.

For the purpose of illustration, it will be assumed that the relayhaving magnet coils I48-- I49--l50 is operated in response to anoperation of the street switch 22A.

It will also be assumed that no trafiic has operated on either streetfor some time, the "go" signal is on the N-S street and that a vehicleapproaches on the E-W street.

The approaching vehicle operates street switch 22A, thereby completing acircuit for energizing magnet coil I50, from positive potential P,through street switch 22A, wires I94I94a; magnet coil I50 to negativepotential N. The energization of magnet coil I50 raises armature II--I5Ib and thereby completes a circuit for energizing auxiliary magnetcoil I49, from positive potential P, through armature I5I, contact I54,wire I95, through contacts 'I2-=-1I, wire I96, magnet coil I49 tonegative potential N. The energization of auxiliary magnet coil I49retains armatures I5II5Ib raised after magnet coil I50 becomesde-energized. With the armatures raised, another circuit for energizingmagnet coil I28 is completed from positive potential P, through armatureI5I, contact I52, wire I99, armature I35e, contact I36, wire 200, wire20017, through contacts I3I309, wire 3I3, magnet coil I28 to negativepotential N. The energization of magnet coil I28 shifts plunger armatureI29 to the left, retaining contacts I3I309 connected and connectingcontact I32 to contact I3I, thereby completing an additional circuit forenergizing electro-magnet 68 via wire 200a. The energization ofelectro-magnet 68 moves bars 63 and 51 to the left, thereby alternatingthe engagement of the stop lugs on member 53 and permitting thecommutator contact segments 53b, via wires 54a and collector rings 55and 56, to de-energize wire 308 and energize wire 301. This alternationin the energization of wires 303 and 301 transfers the go signal fromthe N-S street to the E-W street.

The movement of bar 63 disconnects contacts 1 I 12, which opens thecircuit of auxiliary magnet coil I49 and permits armatures I5I-I5Ib torelease. The releasing of armature I5I deenergizes magnet coil I28 andelectro-magnet 68 by opening the circuit previously established viacontacts I52 and I36. The de-energization of the latter permits plungerarmature I29 to restore to its centrally biased position, and bar 63 torestore to its normal;position through the action of compression spring64. The member 51, however, remains in the position to which it was lastoperated, and retains the "go signal on the E-W street.

The movement of bar 63 also caused contacts 9Ic-9Id to be connected forten seconds by operation of a trigger contact member 9In. With thesecontacts connected, a circuit is completed for energizing magnet coilI34a, from positive potential P, through contacts 9Ic-9I d, wire 204,magnet coil I34a to negative potential N. The energization of magnetcoil I34a raises arma- 75 tu'res I35a-l35dl35c, and thereby prevents asimple transfer of the "go" signal to the N-S street via contacts I52aand NM.

From the foregoing it will be evident that, should a following vehicleoperate street switch 22A within ten seconds after the last operationthereof, the above operations will be repeated. except thatbar 51 willnot be operated again. since it is already in a position to establishthe go" signal on the E-W street. The operation of street switch 22A bya following vehicle will, however, cause another trigger contact memberam to connect further contacts 9Ic-9Id and thereby maintain the circuitfor energizing magnet coil I34a, via wire 204, closed for 10 secondsafter the last operation. Therefore, vehicles following within 10seconds of each other will retain electro-magnet I34a. energized, andthe go signal on the E-W street via the simple method initiallyoutlined.

If more than 10 seconds elapse from the last operation of the E--Wstreet switch 22A, the contacts 9Io-9Id disconnect, therebyde-energizing magnet coil I34a and releasing armatures |35a-I35d--I35c.In the meantime, if no vehicle has operated the N-S street switch 22, nochange in the signal indications will occur, and the go signal willremain on the E-W street to which it was last actuated.

With the "go" signal displaying to the E-W street, and a vehicleoperating the E-W street switch 22A more than ten seconds after the lastoperation thereof, it will be evident that the same operations describedfor the simple method of retaining the go signal will be repeated, butno further change in the position of bar 51 will result, since it isalready in a position to establish the go signal on the E-W street. Atthis time, however, the contacts 9Ic9ld will be re-connected byoperating a trigger contact member em, and thereby re-energize contactcoil I340. for raising its respective armatures to prevent a simpletransfer of the go" signal to the N-S street for at least 10 seconds.

It is important to note that, when the go" signal is transferred to theE-W street, bar 51 is moved to the left, thereby connecting contacts60a- 51e. Therefore, if the wire 200 is energized while the go signal ison the E-W street to bring about a repeated energization of magnet coilI26, a circuit will also be completed for energizing magnet coil I21,from wire 200 via wire 23I, contacts 51e--60a, wire 233, contacts I303I0, wire 3, magnet coil I21 to negative potential N. It is alsoimportant to note that when a vehicle operates the E-W street switch 22Ato bring about a simple transfer of the go" signal from the N--S'totheE-W street, only the single magnet coil I28 is energized. Accordingly,it will be evident-that should a vehicle operate the E-W street switch22A simultaneously with an operation of the N-S street switch 22, withthe "go signal'onthe EW street, the plunger I29 will move to the left byreason of the greater power provided by the energization of magnet coilsI21-I23, and cause the go signal to be retained for an additional 10seconds on the E-W street. If no further vehicles operate the streetswitch 22A, the contacts 9Ic--9Id will disconnect after 10 seconds, andpermit a circuit to be completed via contacts I521: and Ilia to bringabout a simple transfer of the go signal to the N-S street, since theregistration of the vehicle on the N--S street will be retained by relayhaving coils I43a-l49al50a until the auxiliary magnet coil I43a isde-energized by reason of a movement of bar I1.

Paar 2 The positive transfer of the "go signal This method of operatingthe go" signal is employed to transfer the "go signal to traflic waitingwhenever a stream of traflic on another street is retaining the gosignal.

Paar 2A For the purpose of illustrating the automatic positive transferof the "80" signal, it will be assumed that a continuous stream oftrafllc is retaining the go signal on the E-W street via the simplemethod of operation, and that a vehicle approaches on the NS street.

As outlined in Part 1, vehicles continually operating the E-W streetswitch 22A, with 10 seconds after the last operation thereof repeatedlyoperate trigger contact members I, In and retain contacts 3Ic3ldconnected. As long as these contacts are connected, a circuit iscompleted for energizing magnet coil I34a via, wire 204. With magnetcoil I34a energized the armatures. I35a-l35dl35c are raised, therebypreventing a simple transfer of the go signal to the NS street viacontacts I52a and I35a.

The approaching vehicle on the NS street operates street switch 22,thereby completing a circuit for energizing magnet coil I5lla, frompositive potential P, through street switch 22, wires I80-I80a, magnetcoil lilla, to negative potential N. The energization of magnet coilI5Ila raises armatures I 5Ia--I'5Ic and thereby completes a circuit forenergizing the auxiliary magnet coil I43a, from positive potential P,through armature I5Ia, contact I54a, wire I33, through contacts 8483,wire I84, magnet coil H911 to negative potential N. The energization ofauxiliary magnet coil I43a retains armatures I5Ia-I 5 lo raised aftermagnet coil IBIla becomes de-energized. With the armature raised, wireI81 is connected to positive potential P, via contacts I52a and armatureI5Ia, but armature I'35d is raised and disconnected from contacts I36a,thereby preventing a simple transfer of the go signal to NS street.

As previously mentioned, in the description concerning the relativesettings of the timing mechanism, the cam operated contacts IIl9--I Iare connected for definite intervals every two minutes regardless oftraflic conditions. Therefore when the contacts I03I I0 are connected, acircuit is completed for energizing magnet coil I33 and electro-magnet96, from positive potential P, armature IIa, contact I53a, wire 2| I,armature I35a, contact I38a, wire 2I2, contacts 322- 330, wire 304,contacts II-I03, wire 2I3, contact 329-32I, wire 2I3b, wire 2| 6, magnetcoil I33 to negative potential N. The wire 2I3b also connectselectro-magnet 96 through wire 2I6a.

' from positive potential P, through contacts 96d- 96c, wire 2I3b,electro-magnet 96 to negative potential N. The circuit from contactsMid-36c is further completed through wires 2I6b--2I6a 2I6, magnet coilI33 to negative potential N. The energization of magnet coil I33 raisesarmature I35I35e-I35b and thereby prevents further operation to retainthe go signal on the EW street by the simple method via contacts I52 andI36. Therefore the contacts 9Ic-3Id will disconnect 10 seconds after thelast operation of street switch 22A. When the contacts 3Ic 3Iddisconnect, the magnet coil I34a will deenergize and release armaturesI35d-I35d-l35c.

With armature I35d re -connected to contact I360, a circuit is completedfor energizing magnet coil I28a, from positive potential P, througharmature Iila, contact I52a, wire I81, armature I 5d, contact I36a, wirel83a, wire I88, through .contacts I3I'a-3I2, wire 3I5, magnet coil I28ato negative potential N. The energization of magnet coil I23a shiftsplunger armature I23 to the right, retaining contacts I3Ia-3I2 connectedand connecting contact l32a to contact I3Ia, thereby completing anadditional circuit for energizing electro-magnet 13 via wire I30. Theenergization of electro-magnet 19 moves bars 11 and 51 to the right,thereby alternating the engagement oi the stop lugs on member 53 andpermitting the commutator contact segments 53b, via wires 54a andcollector rings 55 and 56, to de-energize wire and energize wire 308.This alternation in the energization of wires 30! and 308 transfers the"go signal from the E W street to the NS street.

The movement of bar 11 disconnects contacts 8483, which opens thecircuit of the auxiliary magnet coil I49a and permits armatures ISM-I5Ic to release. The releasing of armature I5Ia de-energizes magnet coilI28a and electro-magnet I9 by opening the circuit previously establishedvia contacts I52a and I360. The de-energization of the latter permitsplunger armature 129 to restore to its centrally biased position, andbar 11 to restore to its normal position through the action ofcompression spring IIe. 'I'he'member 51, however, remains in theposition to which it was last operated, and retains the go signal on theNS street. g

The movement of bar 11 also caused contacts 93d93c to be connected for10 seconds by operation of a trigger contact member 3311.. With thesecontacts connected, a circuitis completed for energizing magnet coilI34, from positive po-- tential P, through contacts 93d93c, wire 2.03,magnet coil I34, to negative potential The energization of magnet coilI34 retagns armatures I 35I35el35b raised, and thereby prevents a simpletransfer of the "go" signal to the E-W street via contacts I52 and I36.

Shortly after the conflicts 9Ic9ld disconnect, the contacts 96d96c willdisconnect and open the circuit of magnet coil I33, but no furtheroperation will occur at this time, since armatures I35-I35e-I35b areheld raised by magnet coil I34.

Thus the effect of transferring the "go signal, by the automaticpositive change method, is to prevent further operation to retain the gosignal as determined jointly by waiting trafflc and a constantlyoperating time switch, the predetermined time of which operation isentirely haphazard in relation to traflic actuations.

It is to be noted that the signal is not transferred in the positivemanner Just described, unless there has been an operation of the streetswitch on the street to which the "go signal is to be transferred.Therefore, if there is trafllc only on one street, the go signal willremain standing for that street, or if there is no traflic on eitherstreet, the signal will not change, and will remain on the street whereit was last actuated by trafiic. When the go signal is transferred bythe automatic positive change method the warning signal is alsodisplayed, but his desired not to burden or confuse the operation ofPart 2A with the operation of the warning signal, since this isdescribed in detail in Part 5.

PART 23 For the purpose of illustrating the manual positive transfer ofthe "go signal, it will be assumed that a continuous stream of trafflcis retaining the go" signal on the EW street, and that a motorman of anNS street car causes wire 253 to be grounded, via switch I13 and contactsegment B3 or B5 of the NS street, to energize magnet coil l55a.

As outlined in Part 2A, a vehicle operating the NS street switch 22interrupts a continuous stream of trafilc on EW street when thecyclically operated contacts l09-l l0 close.

The operation of the manual positive transfer of the go" signal isidentical with the automatic positive method outlined in Part 2A, exceptthat the transfer of the go signal in the former is made entirelyindependently of the contacts l09-| I0.

When the wire 253 is grounded, magnet coil l56a is energized, therebyshifting plunger armature I51 to the right.. A movement of plungerarmature I51 to the right disconnects all the pairs of contacts normallyengaged in its central position, and connects contacts 323-324, therebycompleting a circuit for energizing magnet coil l50a, from positivepotential P, through contacts 323-324, wires 2l92l9al00a, magnet coil I50a, to negative potential N. With magnet coil 150a energized, the sameseries of operations is established as effected in the automaticpositive transfer of the "go signal.

The plunger armature I51 in moving to the right also electricallyconnects contacts 32l-322, thereby immediately closing the circuitnormally completed by the engagement of contacts I00- i I0. It will beevident therefore, that under the manual positive transfer of thegosignal it is not necessary to wait for an engagement of the contactsi09--l l0, since the operation of plunger I51 simulates the operation ofpart 2A with the immediate closing of the circuit controlled contactsl09--|i0.

Thus the effect of transferring the go" signal by the manual positivemethod is to immediately prevent further operation to retain the gosignal when a motorman of a street car causes wire 253 to be grounded.When the go" signal is transferred by the method outlined in Part 2A thewarning signal is also displayed, but it is desired not to burden orconfuse the operation of Part 23 with the operation of the warningsignal, since this is described in detail in Part 5.

Paar 3 The automatic cyclic transfer of the "a0 signal This method ofoperating the go signal is employed to transfer the .go" signal from onestreet to another at certain times regardless of traflic on eitherstreet.

For the purpose of illustration it will be assumed that no vehicles haveoperated on either street for some time, and that the cam 100d is usedto cause the go signal to be alternately and repeatedly established oneach of the streets.

As previously mentioned, in the description concerning the relativesettings of the timing mechanism, the cam l00d of disk l00b alternatelyand repeatedly closes contacts I I0--l|l and l22--l23, first one pair,followed one-half revolution later by the other pair, and so oncyclically. For the purpose of illustration it will be assumed that diskI00b makes one revolution in two minutes.

It will be assumed that the go signal is on the EW street, and that camI 00d is closing contacts l22-l23, thereby completing a circuit forenergizing magnet coil l50a from positive potential P through contacts323-33I, wire 2", contacts I22I23, wire 220a, contacts 332-324, wires2l82l9a|00a, magnet coil l50a to negative potential N. In the absence ofvehicle operation of the EW street switch 22A, the energization ofmagnet coil |50a will immediately bring about a simple transfer of thego signal to the NS street as outlined in Part 1. The g0 signal willthen be retained on the NS street for at least 10 seconds, and afterthis time will remain on the NS street awaiting further operation. Ifvehicles do not operate either street switch 22 or 22A, the "go" signalwill remain on the NS street for one minute, whereupon contacts 6-1 I!will be closed and complete a circuit for energizing magnet coil I50,from positive potential P through contacts 3l8-320, wire 300, contactsIi-H1, wire 220, contacts 325- 3l'l, wires 30!, 30|a, 194a, magnet coilI50 to negative potential N. This energization of magnet coil I50 willbring about a simple transfer of the go" signal to the EW street. The"go signal will then be retained on the EW street for at leastloseconds, and after this time will remain on the EW street awaitingfurther operation. If vehicles do not operate either street switch 22 or22A, the "go signal will remain on the EW street for one minute,whereupon the contacts I22-l 23 will again be closed to cause a simpletransfer of the go signal to the NS street.

Thus the effect of the automatic cyclic change of the go" signal, in theabsence of vehicle operation, is to transfer alternately and repeatedlythe go" signal from one street to another via the simple method, inwhich case the go" sig transfer of the go signal from the EW street tothe NS street, a vehicle had operated the EW street switch 22A justprior to the closing of contacts l22-l23. As described in Part 1, theoperation of the EW street switch 22A, will cause the "go signal to beretained on the EW street for at least 10 seconds, and will alsoenergize magnet coil Illa to prevent a simple transfer of the go" signalto the NS street during this 10 second period. As previously mentionedin the description concerning the relative settings of the timingmechanism, the cam operated contacts l00-l M are preferably adjusted toclose for a definite interval when the'contacts |22-l23 are operated.Therefore, under these conditions, the closing of contacts l22-I23 willcause an automatic positive transfer of the "go signal to the NS streetas outlined in Part 2A. It will be apparent that a similar operationwill be effected when contacts ll6l I! and H3-l ll are closed to bringabout an automatic cyclic transfer of the "go" signal to the EW streetif a vehicle operates NS street switch 22 just prior to the closing ofcontacts 0-! I1.

is operated to connect contacts 9Ic--9Id for 10 seconds and therebyenergizes magnet coil I34a thr'ough contacts 90d90c, wire 240,disconnecting switch I10, wire 240e, magnet coil I39a to negativepotential N.

A vehicle operating the NS street switch 22 within 15 seconds after theoperation of trigger contact member 9011, will operate the relay havingmagnet coils I 48al50a to bring about a simple transfer of the go signalto the NS street as outlined in Part 1. If the operation of NS streetswitch 22 is made within 10 seconds after the operation of triggercontact member am, then the NS vehicle will be required to. wait untilmember Sin disconnects contacts 9Ic--9Id and permits the go signal to betransferred to: the NS street. n the other hand if the operation of theNS street switch 22 is made within seconds after member 9In disconnectscontacts 9Tc9 Id, then the go signal will be immediately transferred tothe NS street.

In either case, so long as the NS street switch 22 is operated within 15seconds after the operation of trigger contact member 9011., a circuitis completed for energizing magnet coil I, from positive potential P,through street switch 22, wires I902|9a-246, armature I400, contactIlla, wires 241-24Ia, magnet coil I, to negative potential N. Thesubsequent operation of armatures HIS-I451) and the relay having magnetcoils I4BI49-I50 is identical to that outlined in the forepart ofdescription 4A. Therefore, it is apparent that, seconds after the gosignal is transferred to the NS street, it will return automatically toEW street.

It is important to note in the above, that a vehicle operating the NSstreet switch 22, more than 10 seconds after the last operation of theEW street switch 22A, will immediately transfer the go signal to the NSstreet, and if the operation of the NS street switch 22 is withinseconds after the last operation 'of the EW street switch 22A the gosignal will return automatically to the EW street by virtue of anoperation of armat'ure I45b and contact I41, but if more than 15 secondselapse, then armature I451) and contact I41 will not operate to returnthe go" signal to the EW street automatically.

From the foregoing it will be seen that a vehicle between the EW streetswitch 22A and" the intersection, when the go signal is transferred tothe NS street, will be permitted to proceed immediately after tramcceases on the NS street.

Peru 43 For the purpose of illustrating the arterial automatic return ofthe go signaL-it will be assumed that the "go signal is to return alwaysto the NS street. For this purpose disconnecting switches I10, I69 and262 are closed. It is to be noted that, in order to place thedisconnecting switch I69 in circuit with contacts Sud-40o of 15- secondtiming mechanism 90, the disconnecting switch I10 must also be closed.Therefore, whenever the arterial automatic return of the go signal isprovided for the NS street, the vehicleoperated automatic return of thego signal is provided for the EW street.

The principal object of always returning the "go signal to a givenstreet, is to facilitate the movement of traflic thereon. In otherwords, the

street to which the signal is always to return, is'

. For the purpose of illustration, I will assume that the "go signal ison the NS street and that no 'traflic has operated thereon for sometime, and that a single vehicle operates the EW street switch 22A.

The operation of the vehicle-operated automatic return of the g0 signalto the EW street is identical to that outlined in Part 4A.

The operation of the EW street switch 22A energizes magnet coil I50, andraises armatures I5I--I 5Ib to bring about a simple transfer-of the gosignal to the EW street as outlined in Part 1. As further outlined inPart 1, when the go" signal is transferred to the EW street, a triggercontact member 9In is operated to connect contacts 9Ic9ld for 10seconds, and thereby energize magnet coil 134a to prevent a simpletransfer of the "go signal to the NS street for at least 10 seconds.Simultaneously with the operation of trigger contact member em, asimilar trigger contact member 9011. is operated to connect contacts9lld90c for 15 seconds, or for 5 seconds longer than contacts 9Ic9ld.When the contacts 90d90c are connected, a circuit is established forenergizing magnet coil IMa, from positive potential 1?, through contactsSud-90c, wire 240, disconnecting switch I10, wire 258a, disconnectingswitch I69, wire 258, armature I 5Ic, contact I55a, wires 265-235a,magnet coil IMa to negative potential N. The energization of magnet coilIMa raises armatures I45w-I45c. As mentioned in the description of therelay system, armature I450 in raising will not connect contact It'Ia,therefore no change in operation is effected at this time. If novehicles operate the NS street switch 22 for 15 seconds after the lastoperation of the EW street switch 22A, then the go signal will remain onthe EW street for 5 seconds after contacts 9Ic-9Id are disconnected.However, 15 seconds after the last operation of the EW street switch22A, the

to release, which causes armature I450 to con-- nect contact H'Iamomentarily and to complete a circuit for energizing magnet coil I48a,from positive potential P, through armature I450, contact I4Ia, wire240a, disconnecting switch 262, wire 240b, magnet coil 8a to negativepotential N. The energization of magnet coil I48a raises armaturesI5Ia-I5Ic and thereby effects a simple transfer of the go signal to theNS street as outlined in Part 1. Thereafter, if no vehicles operateeither street switch, the go signal will remain on the NS street.

Twill now'assume that a single vehicle operates the NS street switch 22within 10 seconds after an operation of the EW street switch 22A.

The operation of the EW street switch 22A "transfer will cause the "go"signal to be alternately and repeatedly transferred from one street toanotheryia either the simple or positive methods of operation. In thiscase the go signal will be prevented from further change for at least 10seconds after each cyclic transfer, and. in the absence of vehicleoperation on either street during this. period, will remain on thestreet to which it was last actuated, awaiting further operation by thecyclic transfer method or approaching vehicles. It is also apparentthat, 10 seconds after each operation of contacts II6-I II and I22-I 23,the go signal may be retained or transferred according to the simplemethod of operation outlined in Part 1. If it is desired not to have thego signal transferred at fixed intervals, then cam IIIIld is not used.

PART 4' The automatic return of the "go signal -This method of operatingthe go signal is Paar 4A For the purpose of illustrating thevehicle-operated automatic return of the go signal, it will be assumedthat a continuous stream of traffic is retaining the go signal on the EWstreet, and that a vehicle approaches on the NS street. It will beassumed that the go" signal is to be returned to the EW street, and forthis purpose the disconnecting switch I'll) is closed.

It will be remembered that the street switches 22 and 22A are placed.back from the intersection a distance suflicient to permit a vehicle,traveling at the usual rate of speed, to stop before reaching theintersection, if the "go signal is prevented from being immediatelytransferred to the approaching vehicle. With the street switches solocated, it will be evident that it is possible that either a slowmoving vehicle or a stream of vehicles, abruptly stopped by reason of apositive transfer of the go" signal to another street, will not havesuflicient time to, pass the intersection after operating its streetswitch. Therefore, I have provided vehicle actuated means for returningthe go signal to the street from which it was taken, when traflic on theintersecting street ceases. I have further provided that the vehicleoperated return of the go signal will function only when the signal istaken from a street within 15 seconds after the last operation of thestreet switch thereon. That is, if considerable time elapses afteroperation of the street switch on the street receiving the go" signalbefore the go signal is transferred to a cross street, then the go"signal will not be automatically returned, since the 15 second period isarbitrarily selected as representing the time required for slow movingvehicles to pass the intersection.

To provide for the vehicle-operated automatic return of the go signal tothe EW street, the disconnecting switch [III is closed, while to providefor this feature for the NS street, disconnecting switch I'll is closed.Thus the use of the vehicle-operated return of the go signal is setaccording to the requirements of the traffic using the intersection. Forthe purpose of illustration, I will assume that disconnecting switch H0is closed, and disconnecting switches I68, I69, III, 262 and 264 areopened.

As outlined in Part 1,'vehicles continually operating the EW streetswitch 22A, within 10 seconds after the last operation thereof,repeatedly operate trigger contact members 9In and retain contacts8Ic9ld connected for 10 seconds after each operation of a triggercontact member am, which retains magnet coil I34a energized and therebyprevents a simple transfer of the go" signal to the NS street.Simultaneously with the operation of each trigger contact member 9In, asimilar trigger contact member 9011. is also operated to connectcontacts 90d -90c for 15 seconds after each operation of a triggercontact member 901i. Therefore, as long as the simple transfer of the gosignal to the NS street is prevented, and for a period of 5 secondsafter such transfer is granted, contacts 90d.90c remain connected. Aslong as contacts Sod-400 are connected, a circuit is completed forenergizing magnet coil I39a, from positive potential P, through contactsSod-98c, wire 240, disconnecting switch I'III, wire 240e, magnet coilI3Ila to negative potential N. A vehicle operating NS street switch 22while traffic is continually operating the EW street switch 22A,operates relay having magnet coils I48al49al50a to bring about apositive transfer of the go" signal to the NS street as outlined in Part2A.

Incident to the operation of the NS street switch 22, a circuit iscompleted for energizing magnet coil I44, from positive potential P,through street switch 22, wires I-2I9a246, armature I4Ila, contact I4Ia,wires 24'l-24la, magnet coil I44 to negative potential N. Thisenergization of magnet coil I44 raises armatures I45I45b and completes acircuit for energizing auxiliary magnet coil I 43, frompositivepotential P, through armature I400, contact I42a, wire 244,contact I46, armature I45, wire 242, electromagnet, I43 to negativepotential N. The energization of the auxiliary magnet coil I43 retainsarmatures I45I45b raised after the magnet coil I44 becomes de-energized.As mentioned in the description of the relay system, armature I45b doesnot engage contact I" while it is being raised. Therefore, five secondsafter the positive transfer of the go" signal to the NS street, contactsSod-98c disconnect and de-energize magnet coil I39a. The de-energizationof magnet, coil I395; de-energizes magnet coil I43, thereby causingarmatures I45I45b to release. During the movement of armature N51) toits normal released position, it vuill momentarily connect contact I41and energize magnet coil I48, from positive potential P, througharmature l45b, contact I", wires 26311-263, contacts I08aIII8b, wires25Ia-25I, magnet coil I48, to negative potential N. This energization ofmagnet coil I48 raises armatures I5lI5Ib and accordingly registers anoperation for the EW street to bring about a simple transfer of the gosignal to the EW street.

I will now assume that a single vehicle operates the N -S street switch22 within 15 seconds after a single vehicle operated the EW streetswitch 22A.

Under these conditions the go signal is established on the EW street asoutlined in Part 1, in which case a trigger contact member 9m r9,284,810 "energizes magnet coil I50, and raises armatures I5I-I5Ib tobringabout a simple transfer of the go" signal to the EW street, asoutlined in Part 1. As further outlined in Part 1, when the go signal istransferred to the EW street, a 4

tivepotential P, through contacts 811M300, wire 240, disconnectingswitch I10, wire 258a, disconnecting switch I69, wire 258, armatureI5Ic, contact I55a, wires 265-2351;, magnet coil I44a to negativepotential N. The energization of magnet coil I44a raises armaturesI45a'l45c. As mentioned in the description of the relay system, armaturel45c in raising. does not connect contact I41a, therefore no furtheroperation is effected at this time.

A vehicle operating the NS street switch 22 within 10 seconds after theabove described operations, energizes magnet coil I500. and raisesarmatures I5Ia-I5Ic, thereby calling for a transfer of the ,go signal tothe NS street, which is prevented from being immediately transferred tothe NS street by reason of the previous energization of magnet coil I34ain response to the operation of trigger contact member Bln by thevehicle on the EW street. As soon as armature I5I-c disconnects contactI55a, the arterial return circuit of magnet'coil 411 from contacts9Ild9llc is opened, thereby permitting armatures I45a-I45c to release. 9Armature I450 in releasing momentarily connects contact I41a,

and completes a circuit for energizing magnet coil I48a. However, sincearmatures I5IaI5I.c were previously raised in response to anenergization of magnet'coil I50a, no further operation will occur atthis time.

As long as the trigger contact member 91in connects contacts 9011-9010 acircuit is completed for energizing magnet coil I39a from positivepotential P through contact 90d, trigger contact member 9011., contact900, wire 240, disconnecting switch I10, wire 240e, magnet coil I39a, tonegative potential N, thereby raising armatures I 40a--I40c. Therefore,when the NS street switch 22 was operated, an auxiliary circuit wascompleted for the energization of magnet coil I44 from positivepotential P, through street switch 22, wires I80, 2I9a and 246, armatureI40a, contact I4Ia, wires 241-24111, magnet coil I44 to negativepotential N, thereby raising armatures I45--I45b. When armature I45connects contact I 46, a circuit is established for energizing magnetcoil I43 to retain armatures I45-I45b in their operated positions, thelatter circuit being completed from positive potential P througharmature I4I1c, contact I42a, wire 244, contact I46, armature I45, wire242, magnet coil I43, to negative potential N. Asmentioned in thedescription of the relay system, armature I45b does not connect contactI41 while it is being raised.

10 seconds after the operation ofthe E -W street switch 22A, triggercontact member Sln disconnects contacts 9Ie9ld, and thereby dely connectcontact I41. Armature I45b connecttacts Mia-408b, wires 25Ia-25I, magnetcoil the arterial return circuit energizes operating coil 1 :3 fer ofthe "go" signal to the N- -S street, as outlined in Part 1, by virtue ofthe previous energization of magnet'coil Iilla.

As soon as the go. signal is transferred to th NS street, magn I coilI34 is energized to pre- 5 vent a return of the go signal to the 'E-Wstreet, for 10 seconds, and armatures I5Ia,I'5Ic release. When armatureI5Ic releases, it'reconnects contact I55a, and thereby re-establishesthe arterial return. circuit'of magnet coil I44a from contacts Bodc.Therefore, .5 seconds after the transfer of the go signal to the NSstreet, contacts Std-c disconnect, and de-energize magnet coil I44a,which in turn permits armature 50 to release and momentarily connectcontact I41a. Armature I450 connecting contact I41a completes a circuitfor energizing magnet coil I43a, which in turn, raises armaturesI5Ia-I5Ic and operates trigger contact member 9311. to retain the 80signal on the NS street for 10 seconds after the 15 second contacts9lld90c disconnect. The disconnection of contacts Mid-30c alsode-energizes magnet coil I39a, which, in turn, de-energizes magnet coilI43 and permits armature I 45b to release and momentari- 25 ing contactI41 completes a circuit for energizing magnet coil I48 from positivepotential P through armature I45b, contact I41, wires 2530-263, con- I48to negative potential N, and thereby raises armatures I5I-I5Ib to bringabout a vehicleoperated return of the go signal to the';E-W

street, as outlined in Part 4A. Therefore, 10 seconds after the .go"signal is. transferred to the NS street, the trigger contact member 931:disconnects contacts 93d93c, and provides a return of the go signaltothe EW street via the simple method outlined in Part 1, by virtue of theprevious energization of magnet coil I48. As soon as the g signal isreturned to the EW street, trigger contact member 91m re-connectscontacts 9IId-9Ilc, and thereby re-energizes magnet coils I39a-I44a.

Assuming that no further vehicle operation of either street switch 22 or22A is effected, contacts Sod-90c will disconnect 15 seconds after thego signal is returned to the EW street, and de-energize magnet coilsI39a-I44a.. The de-energization of magnet coil I39a. will produce nofurther operation as the NS street switch 22 was not operated during theimmediately preceding 15 seconds. However, the de-energization of magnetcoil I44a.will permit armature 50 to release and momentarily connectcontact I4'Ia to bring about the arterial return of the go signal totheN-S street.

It will be noted that the arterial return circuit for automaticallyreturning the go" signal to the NS street, is completed through armatureI5Ic and contact I55a.

Therefore, for a single operation of the NS street switch 22 within 15seconds after thetransfer of the go signal to the EW street,

I440. after the go signal is transferred to the NS street, and retainsthe go" signal on the NS street for 10 seconds after contacts Sud-90cdisconnect. However, when trafiic continually operates the NS streetswitch 22, the arterial return circuit is retained open. Thus, thevehi-' cle-operated return of the go signal, when used in connectionwith the arterial automatic return, cannot function to transfer the go"signal to the EW street until the go signal has displayed for at least15 seconds on the arterial street, in the event the NS and EW streetswitches are operated within 15 seconds of each other.

Since the arterial automatic return of the "go" signal, outlined in Part413, is effective only when vehicles cease to use the go signal on theEW street, then it is desirable to have this return effective eventhough contacts III9aIlI9b are disconnected. Therefore, disconnectswitch 262 is provided to Jumper these contacts when the NS street ismade arterial. Similarly, when the EW street is made arterial,disconnect switch 264 is closed to jumper contacts IIIBa -IIIIIb.

Explanation of contacts 1080-1081) and. 109a109b Contacts I08aIII8b andIll9al09b are provided to prevent vehicle-operated returns of the gosignal to one street when trafilc continually operates the street switchon an intersecting street.

In the description of the vehicle-operated automatlc return of the gosignal, outlined in Part 4A, it was stated that disconnecting switches264 and 262 were left in theirnormal open positions so that the circuitof magnet coils I48a and I48, respectively, were completed throughcontacts I08aIll8b and I09alli9b.

In the description embracing the relative settings of the timingmechanism, it was pointed out that the latter mentioned contacts arealternately and repeatedly disconnected, first one pair, followed oneminute later by the other pair, and so on cyclically. Taking for examplecontacts IIIBa-I 08b, it will be remembered that these contacts aredisconnected when contacts II3-II4 are connected, and that the contactsII3-I'I4 are employed in bringing about a positive transfer of the "gosignal to the EW street, as outlined in Part 2A.

As described under Part 4A, an operation of the NS street switch 22,while the contacts 90d80c are connected, energizes operating coilsI43-I44 which, in turn, brings about the energization of operating coilI48 to return the go" signal to the EW street seconds after the lastoperation of the NS street switch 22. It will be obvious, therefore,that continual operation of the NS street switch 22 will compel the gosignal to be returned to the EW street via the positive transfer method,outlined in Part 2A. As soon as the go signal is returned to the EWstreet, contacts Sod-90c are 'reconnected, and, since the illustrationassumes continual operation of the NS .street switch 22, thevehicle-operated automatic return feature would re-energize magnet coilI48 and provide an unnecessary return of the go signal to the EW street.To eliminate this unnecessary return of the go" signal, thevehicle-operated automatic return circuit connecting contact I" andoperating coil I48 is opened by the disconnection of contactsIIl8a-I08b. Obviously, therefore, when the vehicle-operated automaticreturn feature is provided for the EW street, cams I05 on disk Illflbare adjusted to maintain contacts I08a-I08b disconnected slightly longerthan contacts Sod-90c are connected.

For the purpose of illustration, I will assume that a single vehicleoperates the EW street I switch 22A, whiletraflic is continuallyoperatnal on the NS street for v10 seconds after each operation of thestreet switch. Therefore, transfer of the go signal to the EW street inresponse to the-single operation of the EW street switch 22A can beaccomplished only by the positive transfer method, outlined in Part Eachoperation of the N-S street switch 22,

as previously mentioned, operates the mechanism to retain the "go signalon the NS street for 10 seconds after each operation. With the go"signal on the NS street, and a vehicle operates EW street switch 22A,magnet coil I50 is energized to call for a transfer of the go" signal tothe EW street. As outlined in vPart 2A when contacts I I3-I I4 aresubsequently connected, magnet coil I33a is energized to discontinueoperation of the mechanism in response to operation of the NS streetswitch 22. Therefore, as soon as the contacts Sid-93c disconnect, magnetcoil I34 is de-energized, and the go signal is transferred to the EWstreet. As outlined in Part 4A, contacts 90d90c remain connected forseconds after the go signal is transferred to'the EW street, which(completes a circuit for energizing magnet coil Since the illustrationis assuming that traffic is continually operating the NS street switch22, the next operation of the NS street switch 22, after the magnet coilI39a is energized, will complete the vehicle-operated return circuit viawires 2I9a-246, and bring about the energization of magnet coilsI43-I44. 15 seconds after the go signal is transferred to the EW street,contacts 90d90c disconnect and de-energize magnet coil I 39a, which, inturn, de-energizes magnet coil I 43 to permit armature I45b to release,and momentarily engage contact I41.

'Howevensince the go signal was transferred to the EW street via thepositive method outlined in Part 2A, contacts Ill8a.-I08b aredisconnected, which prevents an energization of magnet coil I48 to bringabout a vehicle-operated return of the go signal to the EW street.

Thus, a vehicle operated return of the go signal to the EW street isprevented when trafllc is continually operating the NS street atedreturn of the 30" signal is to prevent a slow moving vehicle from beingtrapped between the EW street switch 22A and the intersection, when avehicle operates the NS street switch 22 within 15 seconds after theoperation of the E,W street switch 22A. Obviously, in the foregoingillustration, the EW vehicle, because of continual operation of the NSstreet switch 22, .had suflicient time to approach the intersectionbefore it received its 10 second display of the go" signal. Dependentupon the relative time of operation of the EW street switch 22A, withrespect to the engagement of contacts II3-I I4, the EW vehicle may haveconsiderable time before the positive transfer of the g0 signal outlinedin Part 2A can occur.

Therefore, to illustrate the operation of the vehicle-operated returnunder another condition, it will be assumed that the EW street switch22A is operated while the contacts II3--I I4 are connected.

Under this condition, the go signal is immediately transferred to the EWstreet via the positive method outlined in Part 2A, since Gil thecontacts Il3-II4 are connected. As soon as the go signal is transferredto the EW street, contacts Sod-90c engage, and, since the illustrationis assuming continual operation of the NS street switch 22, the nextoperation of the NS street switch 22 will bring about the energizationof magnet coils I43I44.

As hereinbefore mentioned, contacts III8a-I 08b remain disconnectedslightly longer than contacts 90d90c remain connected. Therefore, sincethe EW street switch 22A was operated while the contacts IIIBa-IIIBbwere disconnected, the latter contacts will reconnect before contacts90d--9llc disconnect. Thus, when contacts 90d-90c disconnect, magnetcoil I43 will be deenergized, and permit armature I45b to momentarilyengage contact I". Contacts I08alll8b being closed at this time, magnetcoil I48 will be energized to provide a vehicle-operated return of thego signal to the EW street, which will not occur until contacts II3-I I4are subsequently connected.

When contacts II3II4 subsequently connect to permit the vehicle-operatedreturn of the go signal to the EW street, the contacts Sod-90c willdisconnect before contacts IIIBa-IIIBb are reconnected, therebypreventing an unnecessary repeated return of the "go signal to the EWstreet.

In the foregoing illustrations, the operation of the vehicle-operatedreturn for the EW street was discussed, and it is to be understood thata similar relation of contacts I09al09b and 92(1-920 will exist whendisconnect switch III is closed to provide the vehicle-operated returnfeature for the NS street.

Peer 5 Warning signal In the usual form of traffic signal system thatnormally alternately and repeatedly displays a go signal to onethoroughfare and then to another, it is customary to display a, warningsignal for a short time before each transfer of the g0 signal. Insystems of this type the constant use of a warning signal is necessary,since the go" signal is operated independently of traffic. Therefore, nodistinction is made between a go signal transfer in the presence oftraiiic over that in the absence of traffic. Thus, when thego signal issubjected to control by vehicles using the intersection, it is notnecessary to display the warning signal before each transfer of the gosignal, but only when the go signal is transferred in such a manner thatit interrupts a continuous stream of traific.

In my invention separate and distinct methods of transferring the g0signal are employed, which differentiate between a transfer of the gosignal from a street on which there is no traffic, and a transfer from astreet on which there is a continuous stream of traffic. In describingthe operation of my invention, I conveniently designated the transfer ofthe go signal from a continuous stream of trafiic, as a positivetransfer of the go signal, which was described in detail in Part 2.Thus, in the operation of my invention, I have provided that the warningsigna1 will be displayed only when the go signal is transferred by thepositive method.

For the purpose of illustration, I will assume that a continuous streamof traffic is retaining the "go signal on the EW street, and that asingle vehicle approaches on the NS street.

Under these conditions of traflic, the go sigml will be operated inexact accordance with the operation outlined in Part 2A. In this plan ofoperating the go" signal, the electro-magnet 96 operates a triggercontact member 9611, and causes the contacts 9611-960 to be connectedfor a time longer than contacts 9Ic9ld. With continuously moving trafficon the EW street, timing member 9| is repeatedly operated. Therefore,the operation of electro-magnet 96, to interrupt the operation of timingmember 9|, will result in the final timing of member 9|, beginningsubstantially at the same time the electro-magnet 96 operates timingmember 96N. As previously described, each trigger member 9610 isprovided with a contact member 96s that is' adapted to connect contacts96t96T for a definite time before the trigger title is restored tonormal by its hooked cam 960. Thus, under the above conditions ofoperation, contacts 96t96T are connected by contact member 96s for adefinite time before hooked cam 9| 0 causes trigger contact member Minto disconnect contacts 9Ic9ld.

It will be noted that, when the contacts 9Ic--9Id are connected, themagnet coil I34a. is energized, thereby holding its armature I350 inengagement with contact I3'Ia,. Therefore, when the contact member 96scauses contacts, 96t96T to connect, a circuit is completed forenergizing magnet coil I64 of the warning signal control relay, frompositive potential P, through armature I350, contact II3a, wire 221,contacts 96t-96T, wires 226223, magnet coil I64 to negative potential N.This energization of magnet coil I64 raises armature I65, whichcompletes the circuit of warning signal 2|, from positive potential P,through armature I65, contact I66, wire 225, warning signal 2I. tonegative potential N.

As soon as the contacts 9Ic9Id are disconnected, the magnet coil I34a4is de-energized, thereby causing armature I350 to open the circuit ofmagnet coil I64 of the warning signal control relay. Thereafter the gosignal will be immediately transferred to the NS street, and contactsMid-96c disconnected, as described in Part 2A.

It will be observed that should the last operation of EW street switch22A be completed somewhat before the NS vehicle causes theelectro-magnet 96 to function, the contacts 9Ic9Id will de-energizeelectro-magnet I34a before contact 96s has left contact 9613. Therefore,the circuit of the warning signal will be energized for a shorter timethan that described previously in Part 5.

Obviously, therefore, the warning signal will display for a fixed timeonly when the triggercontact members 9In and Sin begin their timing atsubstantially the same instant, while the display of the warning signalfor other times will be shortened by the amount of time elapsing betweenthe last operation of a trigger contact member 9In and the subsequentoperation of a trigger contact member 9611.. Therefore, when the amountof time elapsing between the last operation of timing member 9| andtiming member N is equal to the normal time of display of the warningsignal, no warning signal will be displayed. Obviously the display of awarning signal under these conditions is unnecessary since the lastvehicle moving on the EW street will have sufiicient time to pass theintersection beforethe vehicle on the NS street reaches theintersection.

